Hi,
FPR4145 is a hardware appliance, not quite sure how you may deploy it on azure.
1. FTD operates in line with traffic but performs only Intrusion Prevention System (IPS) functions, without full firewall functionality.
2. FTD typically functions by receiving a copy of network traffic for analysis but doesn't actively block or modify traffic.
These are supported, just to put interface in inline-pair mode for scenario 1 and put interface in inline-pair with tap mode for scenario 2.
you may refer below link for more detail
https://www.cisco.com/c/en/us/support/docs/security/firepower-ngfw/200908-configuring-firepower-threat-defense-int.html
3.It operates like a Router without firewall functionality .
It depends how you define firewall functionality.